10 



cox. 



the same in all cases. It is not suriDrising then that there is no siich great 

 uniformity shown in the calorific values of the actual determinations. 



Wood ash contains potassium, sodium, calcium and magnesium in large 

 quantities, chiefly as carbonate, phosphate and sulphate; iron, alumina, 

 chlorine and silica in smaller quantities. It would be noticed that the 

 salt-water woods are quite high in chlorine. Analyses of the ash of 

 Philippine woods follow: 



Table VI. — Analyses of the ivood ash {hark excluded). 



(Numbers give percentages.) 



Constituent, 



Agoho. 



Guava. 



Pototan. 



Bacauan 



Bacao. 



Per cent of ash 



0.61 1.35 1.45 2.26 1.7 



Insoluble in water. 



Silica (SiOo) 



Alumina (AI0O3) 



Ferric oxide (FcoOs) 



Lime (CaO) 



Magnesia (MgO) 



Potash (KoO) and soda (NaoO) 



Phosphoric anhydride (PjOs) 



Sulphuric anhydride (SO3) 



Chlorine (CI) 



Carbon dioxide and undetermined. 



Total insoluble 



1.01 



0.61 



0.68 



0.35 



2.11 



0.43 



0.85 



0.72 



0.52 



0.32 



0.22 



0.22 



30.58 



22.75 



15.14 



32.82 



4.52 



4.51 



3.76 



4.11 



Trace. 



None. 



None. 



None. 



3.50 



9.82 



3.48 



1.86 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



23.91 



11.51 



9.52 



22.77 



66.15 



49.95 



33.65 



62.85 



0.32 

 0.44 

 0.30 

 36.28 

 2.29 



None. 

 1.25 



None. 



None. 

 27.04 



67.92 



Soluble in water. 



Silica (SiOa) 



Alumina (AI2O3) and ferric oxide (Fe203) 



Lime (CaO) 



Magnesia (MgO) 



Potash (K2O) 



Soda (NaoO) 



Phosphoric anhydride (P2O5) 



Sulphuric anhydride (SO3) 



Chlorine (Cl) 



Carbon dioxide and undetermined 



Trace. 



None. 



0.74 



0.89 



9.87 



10.73 



Trace. 

 2.96 

 0.74 

 7.92 



Total soluble 



33.85 



None. 



None. 



0.39 



0.93 



29.30 



2.30 



1.61 



0.71 



14.81 



50.05 



None. 



None. 



0.21 



0.53 



8.15 



30.86 



5.85 



5.71 



15.04 



66.35 



None. 



None. 



1.47 



0.13 



4.37 



15.87 



Trace. 

 1.16 

 4.38 

 9.77 



37.15 



None. 



Trace. 



1.27 



1.06 



4.29 



12.02 



Trace. 

 4,71 

 0.34 

 8.39 



32. C 



Analyses of the residue which remains when woods are burned are very 

 important in determining the relationship of wood gro\\i:h to the mineral con- 

 stituents of the soil and are useful for certain technical dispositions of the ash, 

 but give little clue to the combinations or even the weight of the inorganic 

 matter present in the original material. 



The ash scarcely represents the mineral matter in the wood at all. Perhaps 

 all of the carbon and sulphur of the carbonates and sulphates respectively were 

 present in the organic acid radicals of metallic salts and have already contributed 

 their share to the calorific value of the fuel, still their weight is deducted as 

 inert matter. If the calcium were present as oxalate it would be just to deduct 



